1. Field of the Invention
The present invention relates to a wireless gateway apparatus, a communication system, and a wireless communication method that are capable of wireless communication with wireless field devices in a plant, a factory, or the like.
Priority is claimed on Japanese Patent Application No. 2012-012182, filed Jan. 24, 2012, the content of which is incorporated herein by reference.
2. Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
Conventionally, in order to implement a high level of automated operation in plants, factories, and the like, distributed control systems (DCSs), in which on-site equipment (measurement instruments and actuators) known as field devices are connected to controllers that control the field devices, via a communication means, have been implemented. Although the communication system that forms the core of such distributed control systems conventionally performs communication by cable, in recent years those that communicate wirelessly, conforming to such wireless communication standards such as ISA 100.11a have appeared.
The constitution of a communication system conforming to the above-noted ISA 100.11a wireless communication standard can be broadly divided into field devices capable of wireless communication (wireless field devices), a wireless gateway apparatus, and monitoring apparatuses. The wireless gateway apparatus forms a wireless communication network with field devices, controls the operation of field devices that are joined to the network, and also performs functions that include collection of various data obtained by the wireless field devices. Monitoring apparatuses are connected to the wireless gateway apparatus via a communication line, and monitor the wireless field devices via the wireless gateway apparatus.
Japanese Unexamined Patent Applications, First Publication Nos. 2011-229041 and 2011-205607 disclose examples of communication systems conforming to the above-described ISA 100.11a wireless communication standard. Specifically, these patent references disclose art for reducing the work (work of recording configuration information) required when a field device is newly joined into a wireless communication network.
In the above-described communication systems, a maintenance worker goes on-site, periodically or when a problem arises, to acquire information regarding a wireless field device (hereinafter referred to as device information) and information indicating the connection status between the wireless field device and the wireless gateway apparatus (hereinafter referred to as connection information). In this case, the above-noted device information is characteristic information set into each of the wireless field devices and information indicating the current status of the wireless field device, and the above-noted connection information is information indicating the current number of field device connections to the wireless gateway apparatus and the connection statuses.
The maintenance worker can verify the above-noted device information by the following methods (1) to (3).
(1) The method of visually verifying device information displayed on a display device of the wireless field device.
(2) The method of connecting a dedicated terminal, either wirelessly or by cable, to the wireless field device and, by communicating with the wireless field device, verifying device information acquired by the dedicated terminal.
(3) The method of connecting a dedicated terminal to the wireless gateway apparatus and, by communicating with the wireless field device via the wireless gateway apparatus, verifying device information acquired by the dedicated terminal.
It is also possible for a maintenance worker to verify the above-noted connection information by the following method (4).
(4) The method of connecting a dedicated terminal to the wireless gateway apparatus and, by communicating with the wireless gateway apparatus, verifying connection information acquired by the dedicated terminal.
To verify device information by the above-described methods (1) and (2), it is necessary for the maintenance worker to go to the installation location of the wireless field device. Because many wireless field devices are installed at points that are scattered within a site, and some are installed at high locations that are difficult to reach, the efficiency of work is poor. Also, when verifying device information or connection information by the above-described methods (2) to (4), because it is necessary to operate the dedicated terminal and communicate with the wireless gateway apparatus or the wireless field device, these methods are troublesome.